The hale and hearty soldiers of the Republic benefit most from a healthy constitution, seeing as how it simply increases the amount of vitality you gain after each level-up. More vitality is obviously important to characters that see a fair amount of battle, but keep in mind that the benefits of a high constitution can be emulated by the toughness feats. Rather than expending valuable attribute selection points to gain an extra hit point per level, you may wish to reserve those points for an attribute that more directly affects your character, and simply allot one of your feat slots to toughness or its upgraded brethren. This especially holds true for soldier characters, who will gain more feats than either of the other two classes. A high constitution also affects your fortitude saving throw, allowing you to more easily fight off the effects of poison and other harmful physical ailments, or avoid them altogether.
Some people just don't feel like getting singed by blaster fire every time they step out for a cup of java juice at the cantina. Fortunately, a high intelligence score can make combat skills almost irrelevant, since your intelligence modifier both increases the number of points you can spend on skills, and applies itself to those skills that are most useful for evading battle: repair, computer use, and demolitions.
Wisdom is usually associated with sagacious Jedi Masters, such as Yoda. (Speaking of Yoda of Dagobah moreso than the Clone War-era Yoda, of course.) As such, your wisdom score will be important if you intend to rely on the power of the Force more than the speed of your lightsaber. Your modifier here will increase your Force power reservoir and make it easier for you to resist enemy Force powers. In addition, high wisdom will make your Force powers more difficult for your enemies to defend against. Your wisdom modifier, in addition to adding Force points, is also used to modify your will saving throw, which improves your chances of resisting an enemy's Force powers.
Jedi radiate a sense of internal power that can greatly affect those around them. For that reason, a high charisma will become fairly important after your character becomes a Jedi, when the modifier for the skill starts to apply to certain Jedi-specific feats and Force powers. Even before you feel the calling of the Force, a charismatic individual will have much greater success in persuading others to see his or her side of an argument.
Charisma and wisdom aren't exactly created equal, though, especially for characters that intend to use Force powers as their prime means of affecting the game world and their enemies. If you're planning on playing a Jedi consular who can wield Force powers with ease, you'll definitely want to increase your wisdom stat at the expense of charisma. Even though both of them add their modifier to the DC of a Force power attack, a high wisdom score also increases the amount of Force points your character possesses, as well as your will saving throw.